2008 Consumer Confidence Report

Transcription

1 28 Consumer Confidence Report Water System Name: County Service Area No. 11 Report : July 1, 29 We test the drinking water quality for many constituents as required by State and Federal Regulations. This report shows the results of our monitoring for the period of January 1 - December 31, 28. Este informe contiene información muy importante sobre su agua potable. Si necesita una explicacion del contenido de este reporte llame al numero (65) Type of water source(s) in use: Name & location of source(s): Underground Wells Two Underground Wells in Pescadero Drinking Water Source Assessment information: Prepared by County Environmental Health Services in November 22. Assessment Summary included at end of the Report. Time and place of regularly scheduled board meetings for public participation: of Supervisors Chambers, 4 County Center, Redwood City, CA : am, Tuesday Mornings, Board For more information, contact: Mark Chow, Acting Principal Civil Engineer Phone: (65) Maximum Contaminant (): The highest level of a contaminant that is allowed in drinking water. Primary s are set as close to the s (or Gs) as is economically and technologically feasible. Secondary s are set to protect the odor, taste, and appearance of drinking water. Maximum Contaminant Goal : The level of a contaminant in drinking water below which there is no known or expected risk to health. Gs are set by the U.S. Environmental Protection Agency (USEPA). Public Health Goal (): The level of a contaminant in drinking water below, which there is no known or expected risk to health. s are set by the California Environmental Protection Agency. Maximum Residual Disinfectant (MRDL): The level of a disinfectant added for water treatment that may not be exceeded at the consumer s tap. Maximum Residual Disinfectant Goal (MRDLG): The level of a disinfectant added for water treatment below, which there is no known or expected risk to health. MRDLGs are set by the U.S. Environmental Protection Agency. TERMS USED IN THIS REPORT: Primary Drinking Water Standards (PDWS): s and MRDLs for contaminants that affect health along with their monitoring and reporting requirements, and water treatment requirements. Secondary Drinking Water Standards (SDWS): s for contaminants that affect taste, odor, or appearance of the drinking water. Contaminants with SDWSs do not affect the health at the levels. Treatment Technique (TT): A required process intended to reduce the level of a contaminant in drinking water. Regulatory Action (AL): The concentration of a contaminant, which, if exceeded, triggers treatment or other requirements that a water system must follow. Variances and Exemptions: Department permission to exceed an or not comply with a treatment technique under certain conditions. ND: not detectable at testing limit ppm: parts per million or milligrams per liter (mg/l) ppb: parts per billion or micrograms per liter (ug/l) ppt: parts per trillion or nanograms per liter (ng/l) pci/l: picocuries per liter (a measure of radiation) The sources of drinking water (both tap water and bottled water) include rivers, lakes, streams, ponds, reservoirs, springs, and wells. As water travels over the surface of the land or through the ground, it dissolves naturally-occurring minerals and, in some cases, radioactive material, and can pick up substances resulting from the presence of animals or from human activity. Contaminants that may be present in source water include: G:\USERS\UTILITY\WATER\_CSA-11\CCR\28 CSA 11 CCR.doc

2 28 Consumer Confidence Report CSA No. 11 Page 2 of 5 Microbial contaminants, such as viruses and bacteria, that may come from sewage treatment plants, septic systems, agricultural livestock operations, and wildlife. Inorganic contaminants, such as salts and metals, that can be naturally-occurring or result from urban stormwater runoff, industrial or domestic wastewater discharges, oil and gas production, mining, or farming. Pesticides and herbicides, that may come from a variety of sources such as agriculture, urban stormwater runoff, and residential uses. Organic chemical contaminants, including synthetic and volatile organic chemicals, that are byproducts of industrial processes and petroleum production, and can also come from gas stations, urban stormwater runoff, agricultural application, and septic systems. Radioactive contaminants, that can be naturally-occurring or be the result of oil and gas production and mining activities. In order to ensure that tap water is safe to drink, the USEPA and the state Department of Public Health (Department) prescribe regulations that limit the amount of certain contaminants in water provided by public water systems. Department regulations also establish limits for contaminants in bottled water that must provide the same protection for public health. Tables 1, 2, 3, 4, and 5 list all of the drinking water contaminants that were detected during the most recent sampling for the constituent. The presence of these contaminants in the water does not necessarily indicate that the water poses a health risk. The Department allows us to monitor for certain contaminants less than once per year because the concentrations of these contaminants do not change frequently. Some of the data, though representative of the water quality, are more than one year old. TABLE 1 - SAMPLING RESULTS SHOWING THE DETECTION OF COLIFORM BACTERIA Microbiological Contaminants (to be completed only if there was a detection of bacteria) Total Coliform Bacteria Fecal Coliform or E. coli Highest No. of detections (In a mo.) (In the year) No. of months in violation G Typical Source of Bacteria More than 1 sample in a month with a detection A routine sample and a repeat sample detect total coliform and either sample also detects fecal coliform or E. coli Naturally present in the environment Human and animal fecal waste Lead and Copper (to be completed only if there was a detection of lead or copper in the last sample set) TABLE 2 - SAMPLING RESULTS SHOWING THE DETECTION OF LEAD AND COPPER No. of samples collected 9 th percentile level detected No. sites exceeding AL Lead (ppb) Copper (ppm) AL TABLE 3 - SAMPLING RESULTS FOR SODIUM AND HARDNESS Internal corrosion of household water plumbing systems; discharges from industrial manufacturers; erosion of natural Internal corrosion of household plumbing systems; erosion of natural ; leaching from wood preservatives Sodium (ppm) 11/15/7 57 None None Generally found in ground & surface water Hardness (ppm) 11/15/7 12 None None Generally found in ground & surface water *Any violation of an or AL is marked with an asterisk. Additional information regarding the violation is provided later in this report.

3 28 Consumer Confidence Report CSA No. 11 Page 3 of 5 TABLE 4 - DETECTION OF CONTAMINANTS WITH A PRIMARY DRINKING WATER STANDARD [MRDL] [MRDLG] INORGANIC CHEMICALS Arsenic (ppb) 11/15/ Barium (ppm) 11/15/ Chromium (ppb) 11/15/ (1) Nickel (ppb) 11/15/ Nitrate [NO 3 ] (ppm) 12/9/ RADIOACTIVE CONTAMINANTS Erosion of natural ; runoff from orchards; glass and electronics production wastes Discharge of oil drilling wastes and from metal refineries; erosion of natural Discharge from steel and pulp mills and chrome plating; erosion of natural Erosion of natural ; discharge from metal factories Runoff and leaching from fertilizer use; leaching from septic tanks and sewage; erosion of natural Radium 228 (pci/l) 12/9/ Erosion of natural Gross Alpha Activity [composite result] (pci/l) Uranium [composite result] (pci/l) 3/31/4 6/9/4 9/28/4 12/22/4 3/31/4 6/9/4 9/28/4 12/22/4 VOLATILE ORGANIC CHEMICALS (Monitored in November 27 with Results = ND) None Erosion of natural Erosion of natural TABLE 5 - DETECTION OF CONTAMINANTS WITH A SECONDARY DRINKING WATER STANDARD Chloride (ppm) 11/15/ None Copper (ppm) 11/15/ None Specific Conductance (umhos/cm) 11/15/7 57 1,6 None Sulfate (ppm) 11/15/ None Runoff/leaching from natural ; seawater influence Internal corrosion of household plumbing systems; erosion of natural ; leaching from wood preservatives Substances that form ions when in water; seawater influence Runoff/leaching from natural ; industrial wastes Total Dissolved Solids [TDS] (ppm) 12/28/6 3 1, None Runoff/leaching from natural *Any violation of an, MRDL, or TT is asterisked. Additional information regarding the violation is provided later in this report.

4 28 Consumer Confidence Report CSA No. 11 Page 4 of 5 TABLE 6 - DETECTION OF UNREGULATED CONTAMINANTS Notification Health Effects Language Exempted *Any violation of an, MRDL, or TT is asterisked. Additional information regarding the violation is provided later in this report. Additional General Information on Drinking Water Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants. The presence of contaminants does not necessarily indicate that the water poses a health risk. More information about contaminants and potential health effects can be obtained by calling the USEPA s Safe Drinking Water Hotline ( ). Some people may be more vulnerable to contaminants in drinking water than the general population. Immunocompromised persons such as persons with cancer undergoing chemotherapy, persons who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly, and infants can be particularly at risk from infections. These people should seek advice about drinking water from their health care providers. USEPA/Centers for Disease Control (CDC) guidelines on appropriate means to lessen the risk of infection by Cryptosporidium and other microbial contaminants are available from the Safe Drinking Water Hotline ( ). Summary Information for Contaminants Exceeding an, MRDL, or AL, or a Violation of Any Treatment Technique or Monitoring and Reporting Requirement No exceedances or violations were reported in 28.

5 28 Consumer Confidence Report CSA No. 11 Page 5 of 5 Drinking Water Source Assessment and Protection (DWSAP) Program A source water assessment was conducted for the Well 1 and Well 2 of the County Service Area No. 11 water system in November 22. The source is considered most vulnerable to the following activities not associated with any detected contaminants: Historic waste dumps/landfills Discussion of Vulnerability There have been no contaminants detected in the water supply, however the source is still considered vulnerable to activities located near the drinking water source. The source is most vulnerable to the following activities that were identified within the recharge area for Well 1 and Well 2: 1. Historic Waste Dumps/Landfills Potential source of household and industrial chemicals. 2. Transportation Corridors Road Right-of-ways (herbicide use areas) potential source of herbicides used to control weeds along roadside and potential source of automotive chemicals. 3. Well 2 Waste Transfer/Recycling Stations a potential source of illicitly disposed household, industrial or agricultural chemicals. Also a potential source for bacterial contamination. The CSA 11 public water system conducts routine periodic monitoring of the water quality from Well 1 and Well 2 to ensure that the water supply is safe for human consumption. The well heads are secured and protected from surface flooding. A copy of the complete assessment may be viewed at: Environmental Health Services 2 Alameda de las Pulgas, Suite 1 San Mateo, CA 9443 You may request a summary of the assessment be sent to you by contacting: Gregory Smith Water Protection and Land Use Programs Supervisor (65) (65) (fax) gjsmith@co.sanmateo.ca.us